In Ontario, amateur competitors race at Mosport International Raceway and Shannonville Motorsport Park to earn points towards the regional titles. Championships are contested in the following categories:

• Grand Touring Category – This category is split into two major divisions, the Ontario Challenge Cup for GT1, A-D and the Touring GT Championship (TGTC) for Touring GT, Touring T1 and Touring T2 cars. All the vehicles competing in these classes are prepared to similar rules. They are grouped according to their performance (based on the bracket that a car/driver combination performs). The quickest class, GT1, features cars such as the Ford Mustang and Chevrolet Corvette, while at the other end of the spectrum, GTD and TGTC Touring T2 include vehicles such as the Honda Civic and Volkswagen Rabbit. Some of these cars may be constructed with a tube-frame chassis. The GT1, A-D class races in shorter sprint contests while the Touring GT Championship competitors compete in a twenty-minute sprint race on Saturday. They conclude the weekend with a forty-minute finale.
• Formula Category – These are purpose-built race cars. This is the largest category and there are a variety of regulations that govern these open-wheel cars.
  • Formula 1200 - Uses Volkswagen components and is powered by a 1200-cc air-cooled engine. Drivers compete in the F1200 ISSECO Championship.
  • Formula Ford A, B and C - Utilize the four-cylinder 1600-cc Ford motor with older chassis’ competing in the B and C category. Drivers score points towards the Ontario Formula Ford Challenge.
  • Formula Libre is a race group that includes many classes:
    • Formula First - Utilizes Volkswagen parts but is powered by a 1600-cc air-cooled motor.
    • Formula 2000 - These winged vehicles use a 2.0-liter Ford four-cylinder power-plant.
    • Formula 4 – Is another winged class with the most liberal rules.
• Sports Racer Category – These are purpose-built closed wheel race cars. The class includes a variety of chassis’ which may be constructed by a competitor or a race car manufacturer. There is also a wide range of engine options used by the teams.
• Vintage Automobile Racing Association of Canada – Also competes at CASC-OR weekends and have several classes depending on the age and type of vehicle. Categories include open and closed wheel Historic and Vintage as well as Group 70 for cars produced from the 1970s to 1986.